Oncolytic virus (OV) is a class of antitumor agents that selectively infect and kill tumor cells while sparing normal cells. Among various oncolytic viruses, oncolytic herpes simplex virus type 1 (OHSV-1) is one of the most widely explored agents. OHSV-1 can be constructed through various strategies. It has been investigated in clinical trials for patients with many types of cancers. These clinical studies have shown the safety and efficacy of OHSV-1. This review briefly summarizes the molecular biologic characteristics and advantages of OHSV-1, the development and targeting strategies of OHSV-1, the progresses in research on various OHSV-1 and discusses the currently problems with OHSV-1 in cancer therapy.